Premium
Theoretical description of dissipative vibrational dynamics using the density matrix in the state representation
Author(s) -
Kühn O.,
Malzahn D.,
May V.
Publication year - 1996
Publication title -
international journal of quantum chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.484
H-Index - 105
eISSN - 1097-461X
pISSN - 0020-7608
DOI - 10.1002/(sici)1097-461x(1996)57:3<343::aid-qua7>3.0.co;2-y
Subject(s) - density matrix , wave packet , dissipative system , dephasing , vibrational energy relaxation , operator (biology) , excited state , triatomic molecule , chemistry , physics , potential energy surface , degrees of freedom (physics and chemistry) , molecular vibration , quantum mechanics , relaxation (psychology) , classical mechanics , molecule , quantum , psychology , social psychology , biochemistry , repressor , transcription factor , gene
Ultrafast dissipative dynamics of vibrational degrees of freedom in molecular systems in the condensed phase are studied here. Assuming that the total system is separable into a relevant part and a reservoir, the dynamics of the relevant part can be described by means of a reduced statistical density operator. For a weak or intermediate coupling between the relevant part and the reservoir, it is possible to derive a second‐order master equation for this operator. Using a representation of the reduced statistical operator in an appropriate molecular basis set, vibrational dynamics in a variety of potential energy surfaces can be studied. In the numerical calculations, we focus on the dissipative dynamics under the influence of external laser fields. In the first example, vibrational wave‐packet dynamics and time‐resolved pump‐probe spectroscopy of molecular systems with nonadiabatically coupled excited‐state potential energy surfaces is presented. In the second part, we show how an intense laser field modifies the wave‐packet motion onto two radiatively coupled potential energy surfaces. Finally, the controlled preparation of definite vibrational states in a triatomic molecule with infrared laser pulses is considered taking relaxation and dephasing processes into account. © 1996 John Wiley & Sons, Inc.